Display analysis using scanned images

ABSTRACT

A method for analyzing displays is described. A processing device receives a first scanned image of a first display and determines a first characteristic of the first display by analyzing the first scanned image. The processing device also receives a second scanned image of a second display and determines a second characteristic of the second display by analyzing the second scanned image. The processing device compares the first characteristic and the second characteristic to determine a third characteristic of the second display.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/663,329, filed on Oct. 29, 2012, and incorporated by reference hereinin its entirety.

BACKGROUND

A large and growing population of users enjoy entertainment through theconsumption of digital media items, such as music, movies, images,electronic books and so on. Users employ various electronic devices toconsume such media items. Among these electronic devices are electronicbook readers, cellular telephones, personal digital assistants (PDAs),portable media players, tablet computers, netbooks and the like.

These electronic devices often include a display which can display text,images, videos or other media. Such displays may suffer from variousdefects that reduce a user's enjoyment of digital media consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood more fully from the detaileddescription given below and from the accompanying drawings of variousembodiments of the present invention, which, however, should not betaken to limit the present invention to the specific embodiments, butare for explanation and understanding only. Further, it should beunderstood that the drawings are not necessarily proportional or toscale.

FIG. 1 illustrates a functional block diagram of a display analysissystem.

FIG. 2 illustrates a flowchart of an embodiment of a method of detectinga defect of a mobile device display using a plurality of scanned images.

FIG. 3 illustrates a flowchart of an embodiment of a method ofgenerating a scanned image.

FIG. 4 illustrates a functional block diagram of an embodiment of adefect detection system.

DETAILED DESCRIPTION

Embodiments of a method for analyzing displays of mobile devices aredescribed. The method may be used, for example, during a manufacturingprocess as part of quality control to achieve automated defect detectionin displays of mobile devices. The method may include analyzing ascanned image of a display. By using a scanner to generate the image,lighting is constant and reflections and shadows are eliminated.Further, as opposed to a camera-generated image, a scanned image hasimproved contrast and less distortion introduced by the lens.

In one embodiment, the scanned image of a display used for analysis isgenerated using a commercially available flatbed scanner. Thus, themethod does not introduce significant hardware costs to the analysis ofdisplays. For example, the method may use a fixture on the commerciallyavailable flatbed scanner with the majority of the scanning area coatedsuch that no light leakage is possible. In one embodiment, various colorplanes (e.g., red, green, and blue) of the display are turned on and offmanually by a quality inspector or automatically by a processing device.For each color plane, a full color image on the flatbed scanner iscaptured. In one embodiment, the image is analyzed to determine that thecolor intended to be displayed lies between a maximum value (e.g., 255for an 8-bit image) and an acceptable minimum value (e.g., 200) and thatthe other colors lie between a minimum value (e.g., 0) and an acceptablemaximum value (e.g., 25). In one embodiment, the acceptable minimumvalues and acceptable maximum values are adaptively determined toaccount for changes in the brightness of the display in specific areas.This adaption may be propagated to other color planes to verify aconsistent failure of any plane relative to the other plane's brightnesslevels.

The results of the analysis may be presented to a quality inspectorstating that the display passed or that the display failed to meetquality control requirements. If the display fails, a picturehighlighting the failed plane(s) and/or pixels involved may bepresented. In one embodiment, the location and number of dead pixels maybe saved as a log for later debugging reference. The log may be analyzedto determine if the dead pixels define a cluster of a particular size.This may indicate faulty construction of the various planes used in thedisplay. On the other hand, single defective pixels which are not in acluster may denote broken electronic wiring in the structure.

FIG. 1 illustrates a functional block diagram of a display analysissystem 10. The display analysis system 10 functions to analyze thedisplay 101 of a mobile device 100 placed within or upon the system 10.The display analysis system 10 may analyze the display 101 to determineone or more characteristics of the display 101. For example, the system10 may determine the presence or absence of a defect of the display 101.Thus, the system 10 may be beneficially used during displaymanufacturing as part of quality control. As another example, the system10 may determine an average brightness, a color consistency or a maximumcontrast of the display 101. Thus, the system 10 may be beneficiallyused during display design to measure the efficacy of various designparameters. In addition, the display analysis system 10 may determinecharacteristics of the display 101 other than those described above.

The mobile device 100 may be an electronic book reader, a cellulartelephone, a personal digital assistant (PDAs), a portable media player,a tablet computer, a netbook or any portable, compact electronic device.The display 101 may be a liquid crystal display (LCD), an electronicpaper display, or any another type of display. For example, anelectronic paper display may be a bi-stable LCD display, amicroelectromechanical system (MEMS) display, a cholesteric display, anelectrophoretic display, or another electronic paper display. Oneexample electronic paper display that may be used is an E(electrophoretic) Ink-brand display.

The display analysis system 10 includes an imaging device 110 configuredto image a portion of display 101. The imaging device 110 is configuredto generate a one-dimensional array of pixel values representing theportion of the display 101. The imaging device 110 may be configured togenerate three one-dimensional arrays, each corresponding to a differentcolor (e.g., red, green and blue), or to generate a one-dimensionalarray of color triplets. The imaging device 110 may include a lightsensor that detects an amount of light impinging on the sensor (or uponeach part of the sensor) so as to generate an image or a portion of animage, such as a one-dimensional array of pixel values. In oneembodiment, the light sensor detects visible light. In anotherembodiment, the light sensor detects infrared or ultraviolet light.Thus, the resulting image represents this detection. In one embodiment,the imaging device 110 comprises a charge-coupled device (CCD). Inanother embodiment, the imaging device 110 comprises a complementarymetal oxide semiconductor (CMOS) sensor. The imaging device 110 mayinclude other light sensors. The imaging device 110 may include opticsto direct light towards the light sensor. For example, the imagingdevice 110 may include a mirror or a lens. Because the imaging device110 is configured to generate one-dimensional arrays of pixel values,the imaging device 110 may have only a one-dimensional lens. In anotherembodiment, the imaging device 110 may not include a lens.

The imaging device 110 is mechanically coupled to a motor 130 thatincludes a linear translator 132. The motor 130, using the lineartranslator 132, moves the imaging device 110 (or at least a portionthereof) along a line. In one embodiment, the motor 130 moves a lightsensor of the imaging device 110. In another embodiment, the motor movesa mirror of the imaging device 110 and the light sensor is not moved bythe motor 130.

The linear translator 132 may be a device which moves an object in aline. In one embodiment, the linear translator 132 comprises a reticularchain. In another embodiment, the linear translator 132 comprises abelt. In yet another embodiment, the linear translator comprises a rod.The linear translator 132 may include other components. The imagingdevice 110 is moved by the motor 130 in a line perpendicular to thedimension in which the pixel values of the one-dimensional array ofpixel values are aligned. While being moved by the motor 130, theimaging device 110 generates multiple one-dimensional arrays of pixelvalues for corresponding portions of the display 101. The multipleone-dimensional arrays of pixel values may be concatenated or otherwisecombined to form a two-dimensional image of the display 101.

The display analysis system 10 includes a bed 150 upon which the mobiledevice 100 under test is placed. The bed 150 is at least partiallyoptically transparent. In one embodiment, the bed 150 comprises a glasswindow. The imaging device 110 is oriented towards the bed 150 and thedisplay 101 of the mobile device 100 resting thereon. Similarly, thedisplay 101 of the mobile device 100 under test is oriented towards theimaging device 110.

The display analysis system 10 may include a cover 140 that reduces oreliminates the ambient light detected by the imaging device 110. In oneembodiment, the cover 140 comprises a black cloth that is draped overthe bed 150. In another embodiment, the cover 140 comprises an opticallyopaque film. In one embodiment, the cover 140 includes a cut-out intowhich the device 100 is placed such that the display 101 of the mobiledevice 100 is visible to the imaging device 110 while the remainder ofthe bed is covered by the cover 140.

The display analysis system 10 may include a light source 170 configuredto illuminate the portion of the display 101 imaged by the imagingdevice. In one embodiment, the light source 170 is moved by the motor130 such that the light source 170 and imaging device 110 are fixed withrespect to one another. In one embodiment, the light source 170comprises a xenon light. In another embodiment, the light source 170comprises a cold cathode fluorescent light. In another embodiment, thelight source 170 comprises one or more light emitting diode (LED) linearstrings. The light source 170 may comprise other light-producingcomponents.

The display analysis system 10 includes one or more processing devices120, such as one or more central processing units (CPUs),microcontrollers, field programmable gate arrays, or other types ofprocessing devices. The processing device 120 may be coupled to theimaging device 110 and the motor 130. The processing device 120 maycommunicate with the imaging device 110 to receive image data from theimaging device 110. The processing device 120 may communicate with themotor 130 to provide instructions for moving the imaging device 110 toscan the mobile device 100. In one embodiment, the processing device isfurther coupled to the mobile device 100 under test. The processingdevice 120 may communicate with the mobile device 100 to configure thedisplay 101 into various states as described further below.

The processing device 120 is configured to analyze the image datareceived from the imaging device 110 to determine one or morecharacteristics of the display 101. For example, the processing device120 may determine the presence or absence of a defect of the display 101or may determine an average brightness, a color consistency or a maximumcontrast of the display 101, as will be discussed in more detail below.

The display analysis system 10 also includes a storage device 180coupled to the processing device 120 and configured to store data. Forexample, the processing device 120 may store the results of its analysisof the display 101 on the storage device 180. The storage device mayinclude any combination of volatile and/or non-volatile storage devices.The storage device 120 may also include one or more types of removablestorage and/or one or more types of non-removable storage. The storagedevice 180 may include one or more of read-only memory (ROM), flashmemory, dynamic random access memory (DRAM) such as synchronous DRAM(SDRAM)), or static random access memory (SRAM)). The storage device 180may store an operating system, various program modules, program dataand/or other software components. The storage device 120 may include acomputer-readable storage medium on which is stored one or more sets ofinstructions embodying any one or more of the methodologies or functionsdescribed herein.

In one embodiment, the storage device 180 stores a display defectdetector 185. The display defect detector 185 may be embodied, forexample, as software to analyze one or more scanned images of thedisplay 101 to detect defects in the display 101. The display defectdetector 185, for example, may detect the presence or absence of stuckpixels or dead pixels in the display 101. The display defect detector185 may also determine other characteristics of the display 101 asdescribed in further detail below with respect to FIG. 2.

The display analysis system 10 may further include an output device 190coupled to the processing device 120. In one embodiment, when theprocessing device 120 determines the presence or absence of a defect ofthe display 101, the processing device 120 informs the operator byoutputting an indication of the determination via the output device 190.The output device 190 may include a display screen, a monitor, an alarm,a light, or any other output device.

Some of the components of the display analysis system 10 may be embodiedas a flatbed scanner. For example, in one embodiment the displayanalysis system 10 comprises a flatbed scanner that includes the imagingdevice 110, motor 130, bed 150, and light source 170. The flatbedscanner may include additional or fewer components.

FIG. 2 illustrates a flow diagram of one embodiment of a method 200 ofdetecting a defect of a mobile device display by analyzing a pluralityof scanned images. The mobile device display may be, for example, thedisplay 101 of FIG. 1, and the method may be performed by the displaydefect detector 185.

The method 200 begins, in block 205, with setting the mobile devicedisplay to an on state. In the on state, the pixels of the mobile devicedisplay are set to an on state in response to a request of a qualitycontrol inspector or automatically in response to a predefined event(e.g., when the imaging device is turned on, the mobile device displayis moved to a particular position, etc.). For example, the pixels may beset such that they generate light or reflect ambient light.

In block 210, a scanned image of the mobile device display in an onstate (or white state) is received. The image may be generated as theconcatenation of a plurality of sequentially created one-dimensionalarrays of pixel values. For example, the image may be generated by aflatbed scanner. The image may be stored as a two-dimension matrix ofcolor triplets, each of the color triplets containing three numberscorresponding to red, green, and blue (RGB) or corresponding to hue,saturation, and brightness (HSV).

In block 215, the mobile device display is set to an off state. In theoff state, the pixels of the mobile device display are set to an offstate. For example, the pixels may be set such that they do not generatelight or do not absorb or reflect ambient light. In block 220, a scannedimage of the mobile device display in the off state (or black state) isreceived. In one embodiment, the scanned image is generated, using theflatbed scanner, as the concatenation of a plurality of sequentiallycreated one-dimensional arrays of pixel values.

Although the method 200 may include the reception of two scanned imagesas described above with respect to blocks 210 and 220, the method 200may also include the reception of additional scanned imagescorresponding to a red state, a green state, and a blue state in which,respectively, only the red pixels, green pixels, and blue pixels of thedisplay are set to an on state. As used herein, the term “pixel” alsorepresents elements which may otherwise be referred to as “subpixels”that correspond to specific color values of a pixel. Thus, as usedherein, a single pixel may include a plurality of pixels, e.g., a singlepixel may include a red pixel, a green pixel, and a blue pixel. Themethod 200 may also include setting the mobile device display in the redstate, blue state, and green state. The method 200 may also includesetting the mobile device display into other states, such as a checkeredstate or another patterned state. In another embodiment, the images ofthe mobile device display in the on state and off state are replacedcompletely by images of the mobile device display in the red state, bluestate, green state, or other states.

In block 230, the images are analyzed to determine a characteristic ofthe device. In one embodiment, the determined characteristic is thepresence or absence of a defect of the mobile device display. Asdescribed in detail below, a variety of different defects can bedetermined from analysis of the images.

In one embodiment, the images are analyzed to determine if the mobiledevice display includes one or more dead pixels. A dead pixel is a pixelof the display which does not transition to the on state wheninstructions to do so are given. For example, whereas a dead pixelshould appear white in the on state, it instead appears black. The imageof the mobile device display in the on state may be analyzed todetermine if any pixels of the display have a brightness less than acertain minimum value (e.g. 200 on an 8-bit scale of 0 to 255). If thescanned image is in HSV format, the brightness may be determined as theV value of the portion of the image corresponding to the pixel. If thescanned image is in RGB format, the brightness of the pixel may bedetermined by averaging the RBG values of the portion of the imagecorresponding to the pixel. In another embodiment, the brightness of thepixel is determined by selecting the maximum of the RGB values of theportion of the image corresponding to the pixel or by averaging themaximum and minimum of the RGB values of the portion of the imagecorresponding to the pixel. If the image of the mobile device displayincludes brightness values below a certain minimum value, it may bedetermined that the device includes at least one dead pixel. In oneembodiment, the number and location of dead pixels are stored in a log.

In one embodiment, the images are analyzed to determine if the mobiledevice display includes one or more stuck pixels. A stuck pixel is apixel of the display which does not transition to the off state wheninstructions to do so are given. For example, whereas a stuck pixelshould appear black in the off state, it instead appears white. Theimage of the mobile device display in the off state may be analyzed todetermine if any pixels of the display have a brightness greater than acertain maximum value (e.g., 25 on an 8-bit scale of 0 to 255). Thus, ifthe image of the mobile device display includes brightness values abovea certain minimum value, it may be determined that the device includesat least one stuck pixel. In one embodiment, the number and location ofstuck pixels are stored in a log.

In one embodiment, scanned images with pixels of individual colors in anon state are received from the scanner. For example, a red scanned imagewith only red pixels in an on state, a green scanned image with onlygreen pixels in an on state and a blue scanned image with only bluepixels in an on state may be received. These scanned images may beanalyzed to determine if the mobile device display includes off-colorpixels. An off-color pixel is a pixel of the display that does notdisplay the correct color. For example, whereas an off-color pixelshould appear green in the green state, the color does not appear greenor appears a shade of green outside an acceptable window. The image ofthe mobile device display in each color state may be analyzed todetermine if any pixels of the display have a hue value outside of atolerance window. If the scanned image is in HSV format, the hue valuemay be determined as the H value of the portion of the imagecorresponding to the pixel. If the image of the mobile device displayincludes hue values outside a tolerance window defined for that color,it may be determined that the device includes at least one off-colorpixel. If the scanned image is in RGB format, off-color pixels may alsobe detected by analyzing the RGB values directly. For example, if theimage of the mobile device display in a particular color state (e.g.,green) has a corresponding color value (e.g., G value) outside atolerance window or below a certain value or a different color value(e.g., B value) outside a tolerance window or above a certain value, itmay be determined that the display has at least one off-color pixel. Inone embodiment, the number and location of off-color pixels are storedin a log.

Pixel failure can include more than a typical dead or stuck pixel, suchas localized changes in brightness that indicate a specific threshold offailure but do not go so far as to indicate a full ‘on’ or ‘off’ pixel.In one embodiment, defects such as dead pixels, stuck pixels, oroff-color pixels are detected using an adaptive threshold, that is, athreshold that is pixel-dependent, e.g., different for different pixels.For example, a dead pixel may be determined if a pixel set to the onstate has a brightness which is significantly less than those of itsneighboring pixels. For example, it may be determined that a dead pixelis present if a pixel has a brightness value less than 90% of theaverage of its adjacent pixels. As another example, it may be determinedthat a dead pixel is present if a pixel has a brightness less than 90%of the average of a 5×5 neighborhood of pixels surrounding the pixel. Asa further example, it may be determined that a stuck pixel is present ifa pixel has a brightness value greater than 10% of the average of itsadjacent pixels or those in a neighborhood surrounding the pixel. As yetanother example, it may be determined that an off-color pixel is presentif a pixel has a hue value that differs by more than 5% of the averageof its adjacent pixels or those in a neighborhood surrounding the pixel.Other thresholds or neighborhoods may be used.

In one embodiment, the images are analyzed to determine if the mobiledevice display is uniform. For example, the images may be analyzed todetermine a brightness variance or a color variance and to determinethat the variances are above a threshold to determine the presence of adefect or to determine that the variances are below the threshold todetermine the absence of a defect. In one embodiment, the brightnessvariance is determined by calculating a standard deviation or thevariance of the brightness values of the pixels in the on state. Thevariance is determined as the expected value of the square of thedifference between each brightness value and the mean. The mean isdetermined as the average value of the brightness values. The standarddeviation is determined by taking the square root of the variance.Similarly, a color variance for each color can be determined bycalculating the standard deviation or the variance of the hue values ofthe pixels of the mobile device display in each of the color states.

In one embodiment, the images are analyzed to determine if the variouscolor panes of the display have a consistent intensity. For example, theintensity of each color can be independently measured and compared. Forexample, if the images are in RGB format, the average R value of theimage of the red state, the average G value of the image of the greenstate, and the average B value of the blue state can be compared. Adefect may be detected if the values differ by more than a thresholdamount. In another embodiment, the intensity of each color is comparedpixel by pixel so that local variations in brightness are propagatedthrough the color planes.

As noted above, the determined characteristic of the display may be thepresence or absence of a dead pixel, a stuck pixel, or an off-colorpixel. As another example, the determined characteristic of the displaymay be a brightness variation or a color variation. More particularly,the determined characteristic of the display may be whether or not abrightness variation or color variation exceeds a threshold. In anotherembodiment, the determined characteristic of the display is an averagebrightness or a maximum contrast.

The determined characteristic may be used during a manufacturing processto determine whether the display is defective. The determinedcharacteristic may be used during a design process to determine theefficacy of various design parameters. The method 200 may be repeatedfor different displays to compare the displays. For example, the method200 may be used to determine an average brightness for a series ofdisplays and to track this characteristic over time. If the value istrending downwards, for example, this may indicate a defect in themanufacturing process that can be addressed before the brightness dropsbelow acceptable levels.

The method 200 may be used to determine that a particular display is notuniform with previous displays. For example, a particular display may bedetermined as defective if it is more than a certain amount (e.g., 5%)less than a previously measured display or an average of previouslymeasured displays. As another example, a particular display may bedetermined as defective if it has a red, green, or blue value that ismore than a certain amount (e.g. 10%) different than that of apreviously measured display or an average of previously measureddisplays.

In block 240, the results of the analysis are output. In one embodiment,the output is a message, shown on a monitor, that no defects weredetected or that defects were detected. In one embodiment, if defectsare detected, the nature and location of the defects are shown on themonitor. In one embodiment, the output is a message indicative whetherthe display has met or failed to meet quality control requirements. Forexample, the quality control requirements may allow no more than aparticular number of defective pixels or may only allow a certainbrightness or color variance.

FIG. 3 illustrates a flow diagram of one embodiment of a method 300 ofgenerating a scanned image. The method 300 begins, in block 310, withthe use of an imaging device to generate a one-dimensional array ofpixel values representing a first portion of the display. The displaymay be, for example, the display 101 of FIG. 1. The imaging device maybe the imaging device 110 of FIG. 1. The one-dimensional array of pixelvalues may include a row-array of color triplets, each of the colortriplets containing three numbers corresponding to red, green, and blue(RGB) or corresponding to hue, saturation, and brightness (HSV).

In block 320, the imaging device is moved with respect to the display.The imaging device may be moved in response to initiating a scan. Inparticular, the imaging device may be moved as part of a scan. In oneembodiment, at least a portion of the imaging device is moved and thedisplay does not move. For example, in one embodiment, a light sensor ofthe imaging device is moved and the display does not move. As anotherexample, in another embodiment a mirror of the imaging device is movedand the display does not move. In another embodiment, the display ismoved and the imaging device is not moved. In another embodiment, boththe display and the imaging device are moved. In one embodiment, theimaging device is linearly translated. In another embodiment, theimaging device is rotated.

In block 330, the imaging device is used to generate a one-dimensionalarray of pixel values representing a second portion of the display. Thesteps described in block 320 and 330 may be repeated until a full imageof the display is generated.

In block 340, a scanned image is output. In one embodiment, the scannedimage is used to determine a characteristic of the display. In oneembodiment, the determined characteristic of the display is the presenceor absence of a defect, such as those described above with respect tothe method 200 of FIG. 2

FIG. 4 illustrates an exemplary defect detection system in the form of acomputer system 800 within which a set of instructions, for causing themachine to perform any one or more of the methodologies discussedherein, may be executed. In some embodiments, the machine may beconnected (e.g., networked) to other machines in a LAN, an intranet, anextranet, or the Internet. The machine may operate in the capacity of aserver machine in client-server network environment. The machine may bea personal computer (PC), a set-top box (STB), a server, a networkrouter, switch or bridge, or any machine capable of executing a set ofinstructions (sequential or otherwise) that specify actions to be takenby that machine. Further, while only a single machine is illustrated,the term “machine” shall also be taken to include any collection ofmachines that individually or jointly execute a set (or multiple sets)of instructions to perform any one or more of the methodologiesdiscussed herein.

The exemplary computer system 800 includes a processing system(processor) 802, a main memory 804 (e.g., read-only memory (ROM), flashmemory, dynamic random access memory (DRAM) such as synchronous DRAM(SDRAM)), a static memory 806 (e.g., flash memory, static random accessmemory (SRAM)), and a data storage device 816, which communicate witheach other via a bus 806.

Processor 802 represents one or more general-purpose processing devicessuch as a microprocessor, central processing unit, or the like. Moreparticularly, the processor 802 may be a complex instruction setcomputing (CISC) microprocessor, reduced instruction set computing(RISC) microprocessor, very long instruction word (VLIW) microprocessor,or a processor implementing other instruction sets or processorsimplementing a combination of instruction sets. The processor 802 mayalso be one or more special-purpose processing devices such as anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), a digital signal processor (DSP), network processor,or the like. The processor 802 is configured to execute the displaydefect detector 185 for performing the operations and steps discussedherein.

The computer system 800 may further include a network interface device822. The computer system 800 also may include a video display unit 810(e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)), analphanumeric input device 812 (e.g., a keyboard), a cursor controldevice 814 (e.g., a mouse), and a signal generation device 820 (e.g., aspeaker). The signal generation device 820 may also include a flatbedscanner that generates a signal indicative of a scanned image of mobiledevice display.

A drive unit 816 may include a computer-readable medium 824 on which isstored one or more sets of instructions (e.g., instructions of displaydefect detector 185) embodying any one or more of the methodologies orfunctions described herein. The instructions of the display defectdetector 185 may also reside, completely or at least partially, withinthe main memory 804 and/or within the processor 802 during executionthereof by the computer system 800, the main memory 804 and theprocessor 802 also constituting computer-readable media. Theinstructions of the item ingestion subsystem 108 may further betransmitted or received over a network via the network interface device822.

While the computer-readable storage medium 824 is shown in an exemplaryembodiment to be a single medium, the term “computer-readable storagemedium” should be taken to include a single medium or multiple media(e.g., a centralized or distributed database, and/or associated cachesand servers) that store the one or more sets of instructions. The term“computer-readable storage medium” shall also be taken to include anymedium that is capable of storing, encoding or carrying a set ofinstructions for execution by the machine and that cause the machine toperform any one or more of the methodologies of the present invention.The term “computer-readable storage medium” shall accordingly be takento include, but not be limited to, solid-state memories, optical media,and magnetic media.

Embodiments of the invention also relate to an apparatus for performingthe operations herein. This apparatus may be specially constructed forthe required purposes, or it may comprise a general purpose computerselectively activated or reconfigured by a computer program stored inthe computer. Such a computer program may be stored in a computerreadable storage medium, such as, but not limited to, any type of diskincluding floppy disks, optical disks, CD-ROMs, and magnetic-opticaldisks, read-only memories (ROMs), random access memories (RAMs), EPROMs,EEPROMs, magnetic or optical cards, or any type of media suitable forstoring electronic instructions.

The foregoing description sets forth numerous specific details such asexamples of specific systems, components, methods and so forth, in orderto provide a good understanding of several embodiments of the presentinvention. It will be apparent to one skilled in the art, however, thatat least some embodiments of the present invention may be practicedwithout these specific details. In other instances, well-knowncomponents or methods are not described in detail or are presented insimple block diagram format in order to avoid unnecessarily obscuringthe present invention. Thus, the specific details set forth are merelyexemplary. Particular implementations may vary from these exemplarydetails and still be contemplated to be within the scope of embodimentsof the present invention.

In the above description, numerous details are set forth. It will beapparent, however, to one of ordinary skill in the art having thebenefit of this disclosure, that embodiments of the present inventionmay be practiced without these specific details. In some instances,well-known structures and devices are shown in block diagram form,rather than in detail, in order to avoid obscuring the description.

It is to be understood that the above description is intended to beillustrative and not restrictive. Many other embodiments will beapparent to those of skill in the art upon reading and understanding theabove description. The scope of the present invention should, therefore,be determined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

What is claimed is:
 1. A method comprising: receiving, by a processingdevice, a first scanned image of a first display; determining, by theprocessing device, a first characteristic of the first display byanalyzing the first scanned image; receiving, by the processing device,a second scanned image of a second display; determining, by theprocessing device, a second characteristic of the second display byanalyzing the second scanned image; and comparing, by the processingdevice, the first characteristic and the second characteristic todetermine a third characteristic of the second display.
 2. The method ofclaim 1, wherein the first scanned image and the second scanned imageare generated using a flatbed scanner.
 3. The method of claim 1, whereinat least one of the first scanned image and the second scanned imagecomprises an infrared or ultraviolet image of the first display orsecond display.
 4. The method of claim 1, wherein determining a firstcharacteristic of the first display comprises determining an averageintensity of pixels of the first display.
 5. The method of claim 1,wherein the third characteristic of the second display represents atleast one of presence or absence of a defect in the second display. 6.The method of claim 1, wherein the third characteristic of the seconddisplay represents at least one of an intensity variance or colorvariance of the second display as compared to the first display.
 7. Themethod of claim 1, wherein the third characteristic of the seconddisplay represents an efficacy of a design parameter associated with thesecond display.
 8. The method of claim 1, further comprising outputtingan indication of the third characteristic of the second display.
 9. Asystem comprising: a scanner to generate a first scanned image of afirst display and a second scanned image of a second display, thescanner comprising: an imaging device configured to generate aone-dimensional array of pixel values corresponding to a portion of thedisplay, and a motor configured to move the imaging device with respectto the display; and a processing device communicatively coupled to thescanner to receive the first scanned image and the second scanned image,the processing device to determine a first characteristic of the firstdisplay by analyzing the first scanned image, determine a secondcharacteristic of the second display by analyzing the second scannedimage, and compare the first characteristic and the secondcharacteristic to determine a third characteristic of the seconddisplay.
 10. The system of claim 9, wherein at least one of the firstscanned image and the second scanned image comprises an infrared orultraviolet image of the first display or second display.
 11. The systemof claim 9, wherein the first characteristic of the first displayrepresents an average intensity of pixels of the first display.
 12. Thesystem of claim 9, wherein the third characteristic of the seconddisplay represents at least one of presence or absence of a defect inthe second display.
 13. The system of claim 9, wherein the thirdcharacteristic of the second display represents at least one of anintensity variance or color variance of the second display as comparedto the first display.
 14. The system of claim 9, wherein the thirdcharacteristic of the second display represents an efficacy of a designparameter associated with the second display.
 15. The system of claim 9,further comprising a monitor to output a message representing the thirdcharacteristic of the second display.
 16. A non-transitorycomputer-readable medium having instruction encoded thereon which, whenexecuted by a processing device, cause the processing device to performoperations comprising: receiving, by the processing device, a firstscanned image of a first display; determining, by the processing device,a first characteristic of the first display by analyzing the firstscanned image; receiving, by the processing device, a second scannedimage of a second display; determining, by the processing device, asecond characteristic of the second display by analyzing the secondscanned image; and comparing, by the processing device, the firstcharacteristic and the second characteristic to determine a thirdcharacteristic of the second display.
 17. The non-transitorycomputer-readable medium of claim 16, wherein determining a firstcharacteristic of the first display comprises determining an averageintensity of pixels of the first display.
 18. The non-transitorycomputer-readable medium of claim 16, wherein the third characteristicof the second display represents at least one of presence or absence ofa defect in the second display.
 19. The non-transitory computer-readablemedium of claim 16, wherein the third characteristic of the seconddisplay represents at least one of an intensity variance or colorvariance of the second display as compared to the first display.
 20. Thenon-transitory computer-readable medium of claim 16, wherein the thirdcharacteristic of the second display represents an efficacy of a designparameter associated with the second display.